This invention relates to material-feeding devices and more particularly to a valve-like feeder for charging a pressurized vessel with comminuted material.
In the pulp industry, a variety of valves are used to provide input into pressurized vessels such as digesters and the like. These material-feeding valves are required to provide a pressure seal and this requirement has resulted in the use of feeder valves which do not always effectively transmit material and which require frequent maintenance contributing to loss of production. The problem inherent in the use of conventional valves as feeders for pressurized vessels is due in part to the unbalanced state in which they operate when required to seal feed openings into highly pressurized vessels. Also such feeders very often can only handle wet material in the form of a slurry which can be forceably pushed into the pressurized vessel. This introduces water into the process which turns to steam and increases the heat demand of the system. In addition, the presence of moisture in the system results in less precise control over the process generally and this further adds to the operating time and production costs.